U.S. patent application number 17/012052 was filed with the patent office on 2021-03-18 for electromagnetic relay.
The applicant listed for this patent is OMRON Corporation. Invention is credited to Hiroyuki HARIMOCHI, Hiroyuki IWASAKA, Naoki KAWAGUCHI, Ryota MINOWA, Shinichi OGAWA, Kohei OTSUKA.
Application Number | 20210082650 17/012052 |
Document ID | / |
Family ID | 1000005118560 |
Filed Date | 2021-03-18 |
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United States Patent
Application |
20210082650 |
Kind Code |
A1 |
KAWAGUCHI; Naoki ; et
al. |
March 18, 2021 |
ELECTROMAGNETIC RELAY
Abstract
A movable contact piece is movable in an open direction and a
closed direction with respect to a first fixed terminal and a
second fixed terminal. A first movable contact is connected to the
movable contact piece. The first movable contact is disposed facing
a first fixed contact. A second movable contact is connected to the
movable contact piece. The second movable contact is disposed
facing a second fixed contact. At least one of the first fixed
contact or the first movable contact has a material property
different from that of at least one of the second fixed contact or
the second movable contact.
Inventors: |
KAWAGUCHI; Naoki; (Yame-shi,
JP) ; MINOWA; Ryota; (Yamaga-shi, JP) ;
HARIMOCHI; Hiroyuki; (Kumamoto-shi, JP) ; OGAWA;
Shinichi; (Kikuchi-shi, JP) ; OTSUKA; Kohei;
(Omuta-shi, JP) ; IWASAKA; Hiroyuki;
(Kamimashiki-gun, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OMRON Corporation |
Kyoto-shi |
|
JP |
|
|
Family ID: |
1000005118560 |
Appl. No.: |
17/012052 |
Filed: |
September 4, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01H 50/546 20130101;
H01H 50/641 20130101; H01H 50/44 20130101 |
International
Class: |
H01H 50/54 20060101
H01H050/54; H01H 50/44 20060101 H01H050/44; H01H 50/64 20060101
H01H050/64 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 13, 2019 |
JP |
2019-167424 |
Claims
1. An electromagnetic relay comprising: a first fixed terminal; a
first fixed contact connected to the first fixed terminal; a second
fixed terminal; a second fixed contact connected to the second
fixed terminal; a movable contact piece configured to move in an
open direction and a closed direction with respect to the first
fixed terminal and the second fixed terminal; a first movable
contact connected to the movable contact piece and disposed facing
the first fixed contact; and a second movable contact connected to
the movable contact piece and disposed facing the second fixed
contact, wherein at least one of the first fixed contact or the
first movable contact has a material property different from that
of at least one of the second fixed contact or the second movable
contact.
2. The electromagnetic relay according to claim 1, wherein the at
least one of the first fixed contact or the first movable contact
has a melting point different from that of the at least one of the
second fixed contact or the second movable contact.
3. The electromagnetic relay according to claim 1, wherein the at
least one of the first fixed contact or the first movable contact
has an electric resistance different from that of the at least one
of the second fixed contact or the second movable contact.
4. The electromagnetic relay according to claim 1, wherein the at
least one of the first fixed contact or the first movable contact
includes a conductive material different from that of the at least
one of the second fixed contact or the second movable contact.
5. The electromagnetic relay according to claim 1, wherein the
first fixed contact is made from a first material, and the second
fixed contact is made from a second material different from the
first material.
6. The electromagnetic relay according to claim 1, wherein the
first movable contact is made from a first material, and the second
movable contact is made from a second material different from the
first material.
7. The electromagnetic relay according to claim 1 further
comprising: a movable mechanism configured to support the movable
contact piece such that the movable contact piece is movable in the
open direction and the closed direction; and a drive device
configured to move the movable mechanism, wherein the drive device
includes a coil, a fixed iron core disposed in the coil, and a
movable iron core facing the fixed iron core and connected to the
movable mechanism.
8. The electromagnetic relay according to claim 7, wherein the
first movable contact is configured to contact the first fixed
contact and the second movable contact is configured to contact the
second fixed contact in a state where the movable iron core
contacts the fixed iron core.
9. The electromagnetic relay according to claim 1, wherein a
contact follow of the movable contact piece is less than a sum of
lengths of the first fixed contact and the first movable contact in
a moving direction of the movable contact piece and/or a sum of
lengths of the second fixed contact and the second movable contact
in the moving direction of the movable contact piece.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Japanese Patent
Application No. 2019-167424, filed Sep. 13, 2019. The contents of
that application are incorporated by reference herein in their
entirety.
FIELD
[0002] The present invention relates to an electromagnetic
relay.
BACKGROUND
[0003] For example, an electromagnetic relay includes a movable
contact piece, a movable contact, a fixed contact, and a fixed
terminal as described in Japanese Patent Laid-Open No. 2017-50274.
The movable contact is connected to the movable contact piece. The
movable contact piece moves between an open position and to a
closed position. When the movable contact piece is at the open
position, the movable contact is separated from the fixed contact.
When the movable contact piece is at the closed position, the
movable contact comes into contact with the fixed contact. As a
result, the fixed terminal and the movable contact piece are
energized.
SUMMARY
[0004] When an overcurrent flows through the electromagnetic relay,
a contact may be dissolved. When the contact is dissolved, a gap is
formed between the fixed terminal and the movable contact piece.
This makes it difficult to stably energize the fixed terminal and
the movable contact piece. An object of the present disclosure is
to ensure stable energization in an electromagnetic relay even when
a contact is dissolved.
[0005] An electromagnetic relay according to one aspect includes a
first fixed terminal, a first fixed contact, a second fixed
terminal, a second fixed contact, a movable contact piece, a first
movable contact, and a second movable contact. The first fixed
contact is connected to the first fixed terminal. The second fixed
contact is connected to the second fixed terminal. The movable
contact piece is movable in an open direction and a closed
direction with respect to the first fixed terminal and the second
fixed terminal. The first movable contact is connected to the
movable contact piece. The first movable contact is disposed facing
the first fixed contact. The second movable contact is connected to
the movable contact piece. The second movable contact is disposed
facing the second fixed contact. At least one of the first fixed
contact and the first movable contact has a material property
different from that of at least one of the second fixed contact and
the second movable contact.
[0006] With the electromagnetic relay according to the present
aspect, a timing at which at least one of the first fixed contact
and the first movable contact is dissolved and a timing at which at
least one of the second fixed contact and the second movable
contact is dissolved can be made different from each other, even
when an overcurrent flows. As a result, stable energization can be
ensured even when a contact is dissolved.
[0007] At least one of the first fixed contact and the first
movable contact may have a melting point different from that of at
least one of the second fixed contact and the second movable
contact. In this case, a timing at which at least one of the first
fixed contact and the first movable contact is dissolved and a
timing at which at least one of the second fixed contact and the
second movable contact can be made different from each other due to
the difference in melting point.
[0008] At least one of the first fixed contact and the first
movable contact may have an electric resistance different from that
of at least one of the second fixed contact and the second movable
contact. In this case, a timing at which at least one of the first
fixed contact and the first movable contact is dissolved and a
timing at which at least one of the second fixed contact and the
second movable contact is dissolved can be made different from each
other due to the difference in electrical resistance.
[0009] At least one of the first fixed contact and the first
movable contact may include a conductive material different from
that of at least one of the second fixed contact and the second
movable contact. In this case, a timing at which at least one of
the first fixed contact and the first movable contact is dissolved
and a timing at which at least one of the second fixed contact and
the second movable contact is dissolved can be made different from
each other due to the difference in conductive material.
[0010] The first fixed contact may be made from a first material.
The second fixed contact may be made from a second material
different from the first material. In this case, a timing at which
the first fixed contact and the first movable contact is dissolved
and a timing at which the second fixed contact and the second
movable contact is dissolved can be made different from each
other.
[0011] The first movable contact may be made from a first material.
The second movable contact may be made from a second material
different from the first material. In this case, a timing at which
the first movable contact is dissolved and a timing at which the
second movable contact is dissolved can be made different from each
other.
[0012] The electromagnetic relay may further include a movable
mechanism and a drive device. The movable mechanism may support the
movable contact piece such that the movable contact piece is
movable in the open direction and the closed direction. The drive
device may move the movable mechanism. The drive mechanism may
include a coil, a fixed iron core, and a movable iron core. The
fixed iron core may be disposed in the coil. The movable iron core
may be facing the fixed iron core and be connected to the movable
mechanism. The first movable contact may come into contact with the
first fixed contact and the second movable contact may come into
contact with the second fixed contact in a state where the movable
iron core is in contact with the fixed iron core.
[0013] A contact follow of the movable contact piece may be less
than a sum of the lengths of the first fixed contact and the first
movable contact in the moving direction of the movable contact
piece and/or a sum of the lengths of the second fixed contact and
the second movable contact in the moving direction of the movable
contact piece. In this case, the contact follow enables to improve
a contact pressure of the contacts. In the case where the contact
follow and the contact dimension are in the above relationship, a
gap is likely to be formed between the first and second fixed
terminals and the movable contact piece when all the contacts are
dissolved at the same time. However, in the electromagnetic relay
according to the present aspect, the timing at which at least one
of the first fixed contact and the first movable contact is
dissolved and the timing at which at least one of the second fixed
contact and the second movable contact is dissolved can be made
different from each other, even when an overcurrent flows. As a
result, stable energization can be ensured even when a contact is
dissolved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a side cross-sectional view illustrating an
electromagnetic relay in an opened state according to an
embodiment.
[0015] FIG. 2 is a side cross-sectional view illustrating the
electromagnetic relay in a closed state.
[0016] FIG. 3 is an enlarged view of a contact device when a
movable contact starts contacting a fixed contact.
[0017] FIG. 4 is an enlarged view of the contact device in which a
movable mechanism is at a closed position.
[0018] FIG. 5 is a side cross-sectional view illustrating the
electromagnetic relay according to a modified example.
DETAILED DESCRIPTION
[0019] An electromagnetic relay 1 according to an embodiment will
be explained below with reference to the drawings. FIG. 1 is a side
cross-sectional view illustrating the electromagnetic relay 1
according to the embodiment. As illustrated in FIG. 1, the
electromagnetic relay 1 includes a contact device 2, a housing 3,
and a drive device 4.
[0020] In the following description, the up, down, left, and right
directions indicate the up, down, left, and right directions in
FIG. 1. Specifically, the direction from the drive device 4 toward
the contact device 2 is defined as up(ward). The direction from the
contact device 2 toward the drive device 4 is defined as
down(ward). In FIG. 1, a direction that crosses an up-down
direction is defined as a left-right direction. A direction that
crosses the up-down direction and the left-right direction is
defined as a front-back direction. The front-back direction is a
direction perpendicular to the sheet of FIG. 1. However, these
directions are defined for convenience of description and are not
intended to limit the directions in which the electromagnetic relay
1 is disposed.
[0021] The contact device 2 is disposed in the housing 3. The
contact device 2 includes a movable mechanism 10, a first fixed
terminal 11, a second fixed terminal 12, a movable contact piece
13, a first fixed contact 14, a second fixed contact 15, a first
movable contact 16, and a second movable contact 17. The first
fixed terminal 11 and the second fixed terminal 12 are made from a
conductive material such as copper or copper alloy. The first fixed
contact 14 is connected to the first fixed terminal 11. The second
fixed contact 15 is connected to the second fixed terminal 12. The
first fixed contact 14 and the second fixed contact 15 are disposed
separated in the left-right direction.
[0022] The first fixed terminal 11 includes a first contact support
portion 21 and a first external terminal portion 22. The first
contact support portion 21 faces the movable contact piece 13. The
first fixed contact 14 is connected to the first contact support
portion 21. The first external terminal portion 22 is connected to
the first contact support portion 21. The first external terminal
portion 22 protrudes outward from the housing 3.
[0023] The second fixed terminal 12 includes a second contact
support portion 23 and a second external terminal portion 24. The
second contact support portion 23 faces the movable contact piece
13. The second fixed contact 15 is connected to the second contact
support portion 23. The second external terminal portion 24 is
connected to the second contact support portion 23. The second
external terminal portion 24 protrudes outward from the housing 3.
Specifically, the first external terminal portion 22 and the second
external terminal portion 24 protrude upward from the housing
3.
[0024] The movable contact piece 13 is made from a conductive
material such as copper or copper alloy. The movable contact piece
13 extends in the left-right direction. The movable contact piece
13 is disposed facing the first contact support portion 21 of the
first fixed terminal 11 and the second contact support portion 23
of the second fixed terminal 12 in the up-down direction.
[0025] The movable contact piece 13 is disposed so as to be movable
in a closed direction Z1 and an open direction Z2. The closed
direction Z1 is a direction in which the movable contact piece 13
approaches the first fixed terminal 11 and the second fixed
terminal 12 (upward in FIG. 1). The open direction Z2 is a
direction in which the movable contact piece 13 separates from the
first fixed terminal 11 and the second fixed terminal 12 (downward
in FIG. 1).
[0026] The first movable contact 16 and the second movable contact
17 are connected to the movable contact piece 13. The first movable
contact 16 and the second movable contact 17 are disposed separated
in the left-right direction. The first movable contact 16 faces the
first fixed contact 14 in the up-down direction. The second movable
contact 17 faces the second fixed contact 15 in the up-down
direction.
[0027] The movable mechanism 10 supports the movable contact piece
13. The movable mechanism 10 is disposed so as to be movable in the
closed direction Z1 and the open direction Z2 together with the
movable contact piece 13. The movable mechanism 10 includes a drive
shaft 19, a first holding member 25, a second holding member 26,
and a contact spring 27. The drive shaft 19 extends in the up-down
direction. The drive shaft 19 is connected to the movable contact
piece 13. The drive shaft 19 extends downward from the movable
contact piece 13. The movable contact piece 13 includes a hole 13a.
The drive shaft 19 is inserted into the hole 13a. The movable
contact piece 13 is relatively movable with respect to the drive
shaft 19 in the closed direction Z1 and the open direction Z2.
[0028] The drive shaft 19 is configured to move between a closed
position and an open position. FIG. 1 illustrates the drive shaft
19 at the open position. As illustrated in FIG. 1, the movable
contacts 16 and 17 are separated from the fixed contacts 14 and 15
when the drive shaft 19 is at the open position. FIG. 2 illustrates
the drive shaft 19 at the closed position. As illustrated in FIG.
2, the movable contacts 16 and 17 are in contact with the fixed
contacts 14 and 15 when the drive shaft 19 is at the closed
position.
[0029] The first holding member 25 is fixed to the drive shaft 19.
The contact spring 27 is disposed between the movable contact piece
13 and the first holding member 25. The contact spring 27 urges the
movable contact piece 13 in the closed direction Z1 in a state
where the movable contacts 16 and 17 are in contact with the fixed
contacts 14 and 15. The second holding member 26 is fixed to the
drive shaft 19. The movable contact piece 13 is located between the
second holding member 26 and the contact spring 27.
[0030] The drive device 4 operates the movable contact piece 13 by
electromagnetic force. The drive device 4 moves the movable
mechanism 10 in the closed direction Z1 and the open direction Z2.
As a result, the drive device 4 moves the movable contact piece 13
in the closed direction Z1 and the open direction Z2. The drive
device 4 includes a movable iron core 31, a coil 32, a fixed iron
core 33, a yoke 34, and a return spring 35.
[0031] The movable iron core 31 is connected to the drive shaft 19.
The movable iron core 31 is configured to move in the closed
direction Z1 and the open direction Z2. The coil 32 is energized to
generate electromagnetic force that moves the movable iron core 31
in the closed direction Z1. The fixed iron core 33 is disposed
facing the movable iron core 31. The return spring 35 is disposed
between the movable iron core 31 and the fixed iron core 33. The
return spring 35 urges the movable iron core 31 in the open
direction Z2.
[0032] The yoke 34 is disposed surrounding the coil 32. The yoke 34
is disposed on a magnetic circuit formed by the coil 32. Portions
of the yoke 34 are disposed above, below, and to sides of the coil
32.
[0033] Next, operation of the electromagnetic relay 1 will be
described. When the coil 32 is not energized, the drive device 4 is
not magnetized. In this case, the drive shaft 19 is pressed in the
open direction Z2 by the elastic force of the return spring 35
together with the movable iron core 31. Therefore, the drive shaft
19 is located at the open position illustrated in FIG. 1. In this
state, the movable contact piece 13 is also pressed in the open
direction Z2 via the movable mechanism 10. Therefore, when the
drive shaft 19 is at the open position, the first movable contact
16 and the second movable contact 17 separate from the first fixed
contact 14 and the second fixed contact 15, respectively.
[0034] When the coil 32 is energized, the drive device 4 is
magnetized. In this case, the electromagnetic force of the coil 32
causes the movable iron core 31 to move in the closed direction Z1
against the elastic force of the return spring 35. As a result, the
drive shaft 19 and the movable contact piece 13 move together in
the closed direction Z1. Thus, as illustrated in FIG. 2, the drive
shaft 19 moves to the closed position. As a result, when the drive
shaft 19 is at the closed position, the first movable contact 16
and the second movable contact 17 come into contact with the first
fixed contact 14 and the second fixed contact 15, respectively.
[0035] Specifically, when the drive shaft 19 moves from the open
position to the closed position, as illustrated in FIG. 3, the
first movable contact 16 and the second movable contact 17 come
into contact with the first fixed contact 14 and the second fixed
contact 15, respectively, before the drive shaft 19 reaches the
closed position. This restricts the movement of the movable contact
piece 13 in the closed direction Z1. In this state, the movable
iron core 31 is not in contact with the fixed iron core 33 and is
separated from the fixed iron core 33. Thus, the movable iron core
31 can further moves in the closed direction Z1. Therefore, as
illustrated in FIG. 4, when the drive shaft 19 further moves in the
closed direction Z1, the drive shaft 19 moves in the closed
direction Z1 with respect to the movable contact piece 13. As a
result, the distance between the first holding member 25 and the
movable contact piece 13 decreases, causing the contact spring 27
to be compressed. Therefore, when the drive shaft 19 is at the
closed position, the contact spring 27 urges the movable contact
piece 13 in the closed direction Z1. As illustrated in FIG. 2, when
the drive shaft 19 is at the closed position, the movable iron core
31 comes into contact with the fixed iron core 33. As a result, the
movement of the drive shaft 19 in the closed direction Z1 is
restricted.
[0036] In FIG. 4, "A1" indicates a contact follow. The contact
follow A1 is the distance between a contact start position and the
closed position. The contact start position is a position of the
drive shaft 19 when the first movable contact 16 and the second
movable contact 17 first come into contact with the first fixed
contact 14 and the second fixed contact 15.
[0037] The contact follow A1 of the movable contact piece 13 is
less than a sum A2 of the lengths of the first fixed contact 14 and
the first movable contact 16 in the moving direction of the movable
contact piece 13. The contact follow A1 of the movable contact
piece 13 is less than a sum A3 of the lengths of the second fixed
contact 15 and the second movable contact 17 in the moving
direction of the movable contact piece 13.
[0038] When the current to the coil 32 is stopped and the coil 32
is demagnetized, the movable iron core 31 is pressed in the open
direction Z2 by the elastic force of the return spring 35. As a
result, the drive shaft 19 and the movable contact piece 13 move
together in the open direction Z2. Therefore, as illustrated in
FIG. 1, the movable mechanism 10 moves to the open position. As a
result, when the movable mechanism 10 is at the open position, the
first movable contact 16 and the second movable contact 17 separate
from the first fixed contact 14 and the second fixed contact 15,
respectively.
[0039] In the electromagnetic relay 1 according to the present
embodiment, the first fixed contact 14 and the first movable
contact 16 are made from a first material. The second fixed contact
15 and the second movable contact 17 are made from a second
material. The first material has a material property different from
that of the second material. Specifically, the first material is a
conductive material different from the second material. Therefore,
the first fixed contact 14 and the first movable contact 16 have a
melting point different from that of the second fixed contact 15
and the second movable contact 17.
[0040] The first material and the second material may be selected
from materials known as a contact material. For example, the first
material is a conductive material such as silver, silver alloy,
copper alloy, or tungsten alloy. The second material is a
conductive material such as silver, a silver alloy, a copper alloy,
or a tungsten alloy that is different from the first material.
[0041] In the electromagnetic relay 1 according to the present
embodiment described above, the first fixed contact 14 and the
first movable contact 16 have a material property different from
that of the second fixed contact 15 and the second movable contact
17. Therefore, even when an overcurrent flows, a timing at which
the first fixed contact 14 and the first movable contact 16 are
dissolved and a timing at which the second fixed contact 15 and the
second movable contact 17 are dissolved can be made different from
each other. As a result, even when a contact is dissolved, it is
possible to prevent a gap from being generated between the fixed
terminals 11 and 12 and the movable contact piece 13. Thereby,
stable energization can be ensured between the fixed terminals 11
and 12 and the movable contact piece 13.
[0042] In the electromagnetic relay 1 according to the present
embodiment, the contact follow A1 of the movable contact piece 13
is less than the sum A2 of the lengths of the fixed contacts 14 and
15 and the sum A3 of the movable contacts 16 and 17, respectively.
Therefore, when the fixed contacts 14 and 15 and the movable
contacts 16 and 17 are all dissolved, a gap is generated between
the fixed terminals 11 and 12 and the movable contact piece 13.
However, in the electromagnetic relay according to the present
embodiment, a timing at which the first fixed contact 14 and the
first movable contact 16 are dissolved and a timing at which the
second fixed contact 15 and the second movable contact 17 are
dissolved can be made different from each other, even when an
overcurrent flows. Thereby, stable energization can be ensured
between the fixed terminals 11 and 12 and the movable contact piece
13.
[0043] Although an embodiment of the present invention has been
described so far, the present invention is not limited to the above
embodiment and various modifications may be made within the scope
of the invention.
[0044] The first fixed contact 14 and the second fixed contact 15
may be made from the same material. The first movable contact 16
and the second movable contact 17 may be made from the same
material. The first fixed contact 14 and the second fixed contact
15 may be made from a material different from that of the first
movable contact 16 and the second movable contact 17.
[0045] In the above embodiment, the different material property is
the melting point. However, the different material property may be
another property such as electrical resistance. A different
material property may be achieved by different types of surface
treatment or using different materials for surface treatment.
Alternatively, a different material property may be achieved with
or without applying a surface treatment. The surface treatment may
be plating, cladding, or the like.
[0046] In the embodiment described above, the drive device 4 push
out the drive shaft 19 from the drive device 4 side such that the
movable contact piece 13 moves in the closed direction Z1. Further,
the drive device 4 pulls the drive shaft 19 to the drive device 4
side such that the movable contact piece 13 moves in the open
direction Z2. However, the operation direction of the drive shaft
19 for opening and closing the contacts may be opposite to that in
the embodiment described above. That is, the drive device 4 may
pull the drive shaft 19 toward the drive device 4 side such that
the movable contact piece 13 moves in the closed direction Z1. The
drive device 4 may push out the drive shaft 19 from the drive
device 4 side such that the movable contact piece 13 moves in the
open direction Z2. That is, the closed direction Z1 and the open
direction Z2 may be opposite to those in the above embodiment.
[0047] The shape or disposition of the first fixed terminal 11, the
second fixed terminal 12, or the movable contact piece 13 may be
changed. For example, as illustrated in FIG. 5, the first external
terminal portion 22 and the second external terminal portion 24 may
protrude from the housing 3 in the left-right direction.
Alternatively, the first external terminal portion 22 and the
second external terminal portion 24 may protrude from the housing 3
in the front-back direction. The shape or disposition of the
movable iron core 31, the coil 32, the fixed iron core 33, or the
yoke 34 may be changed. The shape or disposition of the first fixed
contact 14, the second fixed contact 15, the first movable contact
16, or the second movable contact 17 may be changed.
[0048] The first fixed contact 14 may be separated from or
integrated with the first fixed terminal 11. The second fixed
contact 15 may be separated from or integrated with the second
fixed terminal 12. The first movable contact 16 may be separated
from or integrated with the movable contact piece 13. The second
movable contact 17 may be separated from or integrated with the
movable contact piece 13.
[0049] The contact follow A1 of the movable contact piece 13 may be
equal to or greater than the sum A2 of the lengths of the first
fixed contact 14 and the first movable contact 16 in the moving
direction of the movable contact piece 13. The contact follow A1 of
the movable contact piece 13 may be equal to or greater than the
sum A3 of the lengths of the second fixed contact 15 and the second
movable contact 17 in the moving direction of the movable contact
piece 13. Alternatively, the contact follow A1 of the movable
contact piece 13 may be omitted.
REFERENCE NUMERALS
[0050] 4: Drive device, 12: Second fixed terminal, 10: Movable
mechanism, 11: First fixed terminal, 13: Movable contact piece, 14:
First fixed contact, 15: Second fixed contact, 16: First movable
contact, 17: Second movable contact, 31: Movable iron core, 32:
Coil, 33: Fixed iron core
* * * * *